There is an ever-increasing demand for orthopedic devices and prosthetic implants. These devices and implants need to be tested prior to their use within the human body. Testing standards have been or are being formulated for the testing that such devices must undergo. For example, the wear of an orthopedic device, such as a spinal implant, is a critical parameter that needs to be fully tested. For testing the wear of such an orthopedic device, an orthopedic simulator may be employed to subject the orthopedic device to a large number of duty cycles that simulate the motion that the orthopedic device is likely to be subjected to after implantation into a body.
For an orthopedic device, such as a spinal implant, the wear testing may take place in a container or chamber that contains a fluid bath that essentially simulates the internal environment within a body. For example, with a spinal implant, bovine fluid is specified as the fluid in which the test specimen is immersed.
In preparing a specimen for testing within an orthopedic simulator, which will apply various forces along and around different axes, the test specimen will be typically coupled at a test station to the various test machine components which will apply the forces to the test specimen. It is usually a very laborious and difficult process to install a test specimen into a test station. The orthopedic simulators are complicated machines, and access to the holders or adapters for the test specimen is very limited and awkward. Exacerbating this issue, test specimens are often very delicate and the careful removal and insertion of test specimens requires great expertise and a deft touch in order to install the test specimens directly onto the orthopedic simulators.
Once properly installed, and following the application of various forces over millions of cycles in a wear test, the test specimen needs to be inspected for the signs of wear. This includes examining the test specimen and the fluid in which the specimen was immersed for contamination particles. The presence of such particles reveals wearing. A concern with the in situ installation of test specimens at the orthopedic simulators is the potential for contamination of the fluid so that the results of the wear test may be easily compromised.
Another concern with the mounting of test specimens in situ at orthopedic simulators are the difficulties in mounting one-piece specimens. The mounting of such test specimens has proven particularly difficult with conventional orthopedic simulators.